Novoferm garage door opener will not start and shows E4 or a limit error after power‑up.

Safety first: Ensure the door is properly balanced and moves freely by hand before running any automatic learning cycles.

Steps to try:

• Reset control: Disconnect power for 30 seconds and reconnect. Some Novoferm models clear transient limit errors on reboot.
• Reprogram travel limits: Enter programming mode according to your Novoferm model manual (often by holding the "P" or "Set" button). Set the fully closed and fully open positions by running the door to each end and confirming with the program button.
• Check limit sensors: On models with mechanical limit switches on the rail, inspect the cams and switches. Ensure the cams are tight on the shaft and the switches click when actuated. On encoder‑based models, ensure the encoder plug on the motor is fully seated.
• Inspect wiring: With power off, check the harness from the motor/limit assembly to the control board. Reseat connectors and look for pin damage or corrosion.

If the opener cannot store limits or loses them repeatedly, the limit switch assembly or motor encoder may be defective and require replacement.